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Datometry Documentation

Hyper-Q Trace Log File

The Hyper-Q trace log file contains event trace messages. Each line in the trace log file corresponds to a tracer event that is published during the execution of a query.

Several Hyper-Q components publish events, and each event corresponds to a particular client request within a client session. Events can also correspond to a particular backend request. Additionally, events may also correspond to a given log sequence number (LSN) if their session is part of a bulk job, though for normal sessions the LSN field will show a default value of 0.

Every tracer event includes both a tag category and a tag name.

The tag category is an indicator of the type of event, and includes labels such as Preprocessing, Emulation, and Results. The tag category is useful as a filtering mechanism, in case you’re interested in a particular stage of query processing, though it may also be useful as an indicator of when different stages start and end.

The tag name is a more specific label, and indicates what the particular event is for. The tag name is useful for getting a more fine-grained window into the handling of a given query. Events may also include a tag value, which contains additional information about that event. For example, the Start Client Query event includes the text of the client query as the tag value for that event.

Hyper-Q Trace Log Format

The Hyper-Q trace log file is a comma-separated values (CSV) file, a delimited text file that uses a comma to separate values. Each line of the file is a data record. Each record consists of one or more fields, separated by commas.

Table 12. Hyper-Q Trac Log Columns

Column Name

Description

Time

The timestamp when the event occurred, using the local server timezone and formatted with millisecond-precision timestamps as: YYYY-MM-DD HH:MM:SS.mmm

Session ID

The integer session identifier for the session to which the event belongs.

Client Request ID

The universally unique identifier (UUID) identifier for the current client request.

Backend Request ID

The UUID for the current backend request, if applicable.

LSN

An ID generated for bulk jobs that use multiple, parallel sessions. Typically, these connect different sessions with distinct session IDs that are part of the same job.

Tag Category

The tracer event category formatted as both a numeric code prefixed with DLC and a user-readable string. For example: DLC002--Preprocessing

Tag Name

The tracer event name, formatted as both a numeric code prefix with DLE and a user-readable string. Foe example: DLE0003--Start Client Query

Tag Value

The tracer tag value (if included in the event). This value is free-form, and may span multiple lines, with the meaning of the value dependent on the particular event.



 

Hyper-Q Trace Log Categories

Hyper-Q logs the following categories in the trace log.

Table 13. Hyper-Q Trace Log Categories

Category Code

Category Name

DLC002

Pre-processing

DLC003

Execution

DLC004

Results

DLC005

Metadata

DLC006

Logic processing

DLC007

Fast export

DLC008

Feature extraction

DLC009

Emulation

DLC010

Debug



Hyper-Q Trace Log Events

Hyper-Q logs the following events.

Table 14. Hyper-Q Trace Log Events

Event Code

Event Name

Verbosity

DLE0003

Start Client Query

2

DLE0055

Start XC Request Handling

5

DLE0004

Start Binding

5

DLE0005

Start Transformation

5

DLE0006

Start Serialization

5

DLE0007

Start Data Conversion

2

DLE0008

Query Sent to Backend

2

DLE0009

Query Completed

2

DLE0010

Error

1

DLE0011

Start Catalog Lookup

4

DLE0012

Catalog Lookup Completed

4

DLE0013

Start MD-Store Lookup

4

DLE0014

MD-Store Lookup Complete

4

DLE0019

Start Transaction Abort

2

DLE0021

Start Parameterized Query

5

DLE0023

Initialize MD-Store Update

4

DLE0024

MD-Store Update Complete

4

DLE0025

Intermediate Query Response Received

3

DLE0026

Fetch Chunk Complete

5

DLE0027

Start TDF Cursor Query

4

DLE0028

TDF Cursor Query Complete

4

DLE0029

Query Cancelled

4

DLE0030

Row Count

4

DLE0031

Bulk Load Session

1

DLE0032

Start MD-Store Update

4

DLE0033

Client Query Hash

2

DLE0034

CTAS with UPI

4

DLE0035

DML with Quantified Subquery

4

DLE0036

Emulate Sequence

4

DLE0037

Enforce SET Table INSERT

4

DLE0038

UPI INSERT

4

DLE0039

UPI UPDATE

4

DLE0040

UPDATE with Join

4

DLE0041

UPDATE Temp Table in Xact

4

DLE0042

SET Table INSERT

4

DLE0043

SET Table INSERT Values

4

DLE0044

MERGE

4

DLE0045

SET Table UPDATE

4

DLE0046

MLOAD Uniqueness Check

4

DLE0048

Materialize GTT

4

DLE0049

Eliminate Nested Case Expressions

4

DLE0050

Quantified Subquery With Long Const List

4

DLE0051

Start Fetch Chunk

5

DLE0053

DEBUG

4

DLE0054

Client Query Config

2

DLE0060

Query Type Select

2

DLE0061

Query Type DDL

2

DLE0062

Query Type DML

2

DLE0063

Query Type Other